The state of the art of implantable pulse generators for stimulating human tissue has advanced to the point that such devices are being designed and used in increasing numbers to treat a wide variety of medical conditions. In addition to implantable pulse generators for treating many different types of cardiac conditions (bradycardia, tachycardia, fibrillation, and the like), so-called neurological pulse generators have been provided for stimulating a patient's nervous system, in order to treat such diverse conditions as pain, motor impairment, incontinence, and impotence, to name only a few.
In most cases, electrical stimulating pulses are conveyed from an implanted pulse generator to the desired stimulation site by means of an implanted lead having exposed electrodes at its distal end. The proximal end of the lead is coupled to the pulse generator by one of many known types of connector mechanisms, after the distal end of the lead has been placed in the desired position in the patient.
In order to achieve the desired effects from delivery of stimulating pulses from an implantable pulse generator, it is of course very important that the lead be properly positioned in the patient, so that as much of the stimulating energy as possible is delivered to the appropriate site. While this is true for all kinds of stimulating pulse therapies, lead positioning is especially critical in the area of neurological stimulation, such as when stimulating pulses are delivered by a lead positioned in the epidural space adjoining the patient's spinal column. The delicate and highly sensitive nature of the spinal column, and the possible harmful or otherwise undesirable effects of delivering stimulating pulses to an inappropriate site in this area, accentuates the need for precise lead placement in such cases.
In order to determine and/or verify the proper placement of a neurological stimulating lead in a patient, a so-called `screening` procedure is often carried out in conjunction with the implantation of the lead. During the screening procedure, the lead may be initially and temporarily connected to an external device capable of simulating the operation of the pulse generator to be implanted. One such external device is the Model 3625 Neurological Screener available from Medtronic, Inc., Minneapolis, Minn. With an external device such as the 3625 Screener coupled to the lead, the effects of the stimulating pulses can be observed and placement of the lead can be adjusted to achieve optimal results, prior to fully completing the implantation of the pulse generator.
Typically, the proximal, or connector, end of the implantable lead is adapted to be connected to the implantable pulse generator. As a result, the connector end is preferably designed to be as compact as possible, and is usually not designed to be conveniently coupled to anything but the implantable pulse generator. Thus, in the prior art, temporarily coupling the connector end of the lead to a screening device or other external accessory often involves an expensive connector block similar to that normally found on the implanted device. Alternatively, "alligator" clips or the like may be used.
The present invention relates to a connector designed to connect implantable leads to an external cable during and/or following implantation of the lead, in order to facilitate trial sensing or stimulation, electrode positioning, and patient response prior to the more permanent connection of the lead to an implantable pulse generator or the like.